1. Field of the Invention
This invention relates to a deployable antenna.
2. Description of the Related Art
The deployable antenna is transported in a folded state because of its limited stowage capacity during the transportation from ground to orbit. After transported to the orbit, the deployable antenna in the folded state is deployed as an antenna in the orbit.
FIGS. 1, 2, and 3 are illustrations of a deployable antenna A0 according to the related art. FIG. 1 is a view of the deployable antenna A0 as obliquely viewed to its front surface. FIG. 2 is a view of the deployable antenna A0 as obliquely viewed to its back surface. FIG. 3 is a view illustrating the back surface of the deployable antenna A0.
The deployable antenna A0 is a large deployable antenna having an aperture diameter size exceeding 10 m. In the deployable antenna A0 illustrated in the figures, a plurality of deployable antenna modules A1 (FIG. 1) are jointed to and driven in association with one another by joint members 40 (FIG. 3), to thereby attain the deployable antenna having a large aperture diameter. In the deployable antenna A0 illustrated in the figures, deployment driving mechanisms 30 (FIGS. 2 and 3) are provided to the respective deployable antenna modules A1, resulting in an increase in number of the deployment driving mechanisms 30 to be used, which are hard to reduce in weight. Consequently, there is a disadvantage that the mass of the deployable antenna A0 increases.
As described above, the module diameter size of each deployable antenna module A1 is smaller than the aperture diameter size of the deployable antenna A0. Therefore, in order to obtain the deployable antenna A0 having a large aperture diameter, a plurality of deployable antenna modules A1 need to be jointed to one another to increase the area of the antenna. However, in the method of jointing a plurality of deployable antenna modules A1 to one another to attain the deployable antenna A0, the number of the deployment driving mechanisms 30 to be used for the deployable antenna A0 increases, which leads to the disadvantage that the mass of the entire antenna increases.
Japanese Unexamined Patent Application Publication (JP-A) No. 2006-80577 discloses, in FIG. 3 and paragraphs [0024] and [0025], that each frame 2 is constructed of five planar links 3, and that the adjacent planar links 3 are jointed to each other in a mirror-image relationship.
Further, Japanese Unexamined Patent Application Publication (JP-A) No. 2006-80577 discloses, in FIG. 4 and paragraphs [0026], [0028] to [0031], and [0033], that the slide hinge 7 of each planar link 3 is moved by the wire driving device (extending means) 11 (corresponding to the deployment driving mechanism described above) to fold and unfold the frame 2.
However, as illustrated in FIG. 4 of Japanese Unexamined Patent Application Publication (JP-A) No. 2006-80577, the link member 4c of each planar link 3 is provided with the slide hinge 7, but the link member 4a opposed to the link member 4c is not provided with any slider for synchronized unfolding between the two adjacent planar links.
International Patent WO2005/027186A discloses, in FIG. 2 and lines 21 to 24 of page 7, that each frame 2 is constructed of five planar links 3, and that the adjacent planar links 3 are jointed to each other in a mirror-image relationship.
Further, International Patent WO2005/027186A discloses, in FIG. 3, lines 31 to 42 of page 7, and lines 48 to 50 of page 7, that the slide hinge 7 of each planar link 3 is moved by the wire driving device (extending means) 11 (corresponding to the deployment driving mechanism described above) to fold and unfold the frame 2.
However, as illustrated in FIG. 3 of International Patent WO2005/027186A, the link member 4c of each planar link 3 is provided with the slide hinge 7, but the link member 4a opposed to the link member 4c is not provided with any slider for synchronized unfolding between the two adjacent planar links.
Japanese Unexamined Patent Application Publication (JP-A) No. Hei 11-112228 discloses, in FIGS. 1 and 2 and paragraph [0025], the planar truss 1 in a state of being unfolded into a rectangular shape.
However, as illustrated in FIG. 2 of Japanese Unexamined Patent Application Publication (JP-A) No. Hei 11-112228, the central member 21 of the planar truss 1 is provided with the slider 27, but the peripheral member 22 opposed to the central member 21 is not provided with any slider similarly to Japanese Unexamined Patent Application Publication (JP-A) No. 2006-80577 and International Patent WO2005/027186A.
Japanese Unexamined Patent Application Publication (JP-A) No. 2003-95199 discloses, in FIGS. 1(a) and 1(b), FIG. 2, and paragraph [0019], the deployable antenna in which the bone members 14 each having two four-node links 12 and 13 continuously connected together are disposed around the central vertical beam member 11. As illustrated in FIG. 4 of Japanese Unexamined Patent Application Publication (JP-A) No. 2003-95199, in the disclosed deployable antenna, the synchronization mechanism 19 serving as unfolding synchronization means is provided to the central vertical beam member 11 so as to be movable in the axial direction thereof. One end of the synchronization cable 20 is fixed to the synchronization mechanism 19, and the other end of the synchronization cable 20 is fixed in the vicinity of the hinge of the inclined member 123 of the four-node link 12 of the bone member 14 under a state in which the synchronization cable 20 is looped around the guide pulley 201.
However, both the vertical beam member 122 opposed to the central vertical beam member 11 and the vertical beam member 132 opposed to the vertical beam member 122 are not provided with any slider similarly to Japanese Unexamined Patent Application Publication (JP-A) No. 2006-80577 and International Patent WO2005/027186A.